Conventionally, internal combustion engines are thermo-dynamically classified into Otto cycle, Diesel cycle and Sabathe cycle, while they are operationally classified into 2-cycle engines and 4-cycle engines. These internal combustion engines are operated so that each piston in each cylinder performs an intake stroke, compression stroke, combustion stroke and exhaust stroke. The motions of the pistons are transmitted through connecting rods to a crank shaft, thereby converting the reciprocating movements to revolving motions. In these internal combustion engines, the pistons and the crank shaft undergo great variations of pressure and torque, and therefore, the engine receives severe impact and vibration, with the result that noises are severely generated, and that the abrasions of the mechanical parts are severe. Consequently, the upper and lower limits of the revolution speed are restricted, and if smooth operation in these internal combustion engines is to be realized, a large flywheel is required, with the result that the volume and the weight of the engine cannot be miniaturized. Further, due to the risk of causing back fire, high speed operation cannot be achieved.
Further, the intake time and exhaust time are very short, and therefore, the charging of the fresh air and discharging of the exhaust gas to and from the cylinder are incomplete, thereby reducing the output level.
Accordingly, a supercharger has to be used additionally, and further, the exhaust gas has to be discharged without having a combustion delaying effect, with the result that the thermal efficiency drops to a great degree.
In an attempt to overcome the above described disadvantages, the rotary engine was developed, but, in this rotary engine, the rotor and the eccentric shaft are connected through gears, with the result that noises are generated during driving. Further, air-tight sealing and lubrication between the rotor and the casing become difficult. If a malfunction occurs on the rotor or on the casing, it is difficult to repair. Manufacture is also difficult.